Many yo-yo tricks require the yo-yo to spin freely at the end of the string without climbing up the string. A yo-yo spinning freely at the end of the string is commonly said to "sleep" or "dwell." Ideally, a player will cause the yo-yo to sleep, and perform the desired trick while the yo-yo is spinning. After the trick has been executed, the player tugs on the string and the yo-yo climbs up the string again (referred to herein as "waking up" the yo-yo).
The sleep time for a yo-yo will typically increase as the angular momentum of the yo-yo increases. Angular momentum is a function of the rotational speed of the yo-yo and the weight distribution in the yo-yo. It is known to provide a weighted ring that may be mounted on or removed from the yo-yo to alter the yo-yo's angular momentum.
Another factor in performing yo-yo tricks is the weight of the yo-yo. Some tricks are more easily performed with a lighter-weight yo-yo, and some tricks require a heavier yo-yo. Some yo-yo players own several yo-yos of various weights to perform these various tricks.